// Ceres Solver - A fast non-linear least squares minimizer
// Copyright 2015 Google Inc. All rights reserved.
// http://ceres-solver.org/
//
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// Author: sameeragarwal@google.com (Sameer Agarwal)

#include "ceres/block_random_access_dense_matrix.h"

#include <vector>
#include "ceres/internal/eigen.h"
#include "glog/logging.h"

namespace ceres {
namespace internal {

BlockRandomAccessDenseMatrix::BlockRandomAccessDenseMatrix(
    const std::vector<int>& blocks) {
  const int num_blocks = blocks.size();
  block_layout_.resize(num_blocks, 0);
  num_rows_ = 0;
  for (int i = 0; i < num_blocks; ++i) {
    block_layout_[i] = num_rows_;
    num_rows_ += blocks[i];
  }

  values_.reset(new double[num_rows_ * num_rows_]);

  cell_infos_.reset(new CellInfo[num_blocks * num_blocks]);
  for (int i = 0; i < num_blocks * num_blocks; ++i) {
    cell_infos_[i].values = values_.get();
  }

  SetZero();
}

// Assume that the user does not hold any locks on any cell blocks
// when they are calling SetZero.
BlockRandomAccessDenseMatrix::~BlockRandomAccessDenseMatrix() {
}

CellInfo* BlockRandomAccessDenseMatrix::GetCell(const int row_block_id,
                                                const int col_block_id,
                                                int* row,
                                                int* col,
                                                int* row_stride,
                                                int* col_stride) {
  *row = block_layout_[row_block_id];
  *col = block_layout_[col_block_id];
  *row_stride = num_rows_;
  *col_stride = num_rows_;
  return &cell_infos_[row_block_id * block_layout_.size() + col_block_id];
}

// Assume that the user does not hold any locks on any cell blocks
// when they are calling SetZero.
void BlockRandomAccessDenseMatrix::SetZero() {
  if (num_rows_) {
    VectorRef(values_.get(), num_rows_ * num_rows_).setZero();
  }
}

}  // namespace internal
}  // namespace ceres
